Archive for the ‘R1KT’ Category

About the first of the month, two-year-old RH92 was reported to have started her annual molt. She joins four other seals known to have molted this year thus far: R1KT, R3CX, RG22, and V2.

Photo credit: Lynn Nowatzki

Hawaiian monk seals experience what’s called a “catastrophic molt,” meaning the loss of the top layer of skin and fur happens in one concentrated period of time, rather than continually throughout the year. The molting process can take one to two weeks. Because molting requires great energetic resources, during this time, the seal will usually stick pretty close to the beach, often spending the night tucked high up the beach and under bushes.

Molting is a vulnerable time for monk seals, another reason to encourage folks to keep dogs on leashes. Typically, the molt starts on the belly, flippers, muzzle, and scars. Then, moves to the back. The molting pattern isn’t exactly “attractive.” A seal with patches of dead skin falling off can often cause beach-goers concern, thinking the seal is sick or, even, dead.

Adult females will often molt soon after they wean their pups. Also, any seals outfitted with a telemetry tag near its molt will lose it during the molt. (If you happen upon a telemetry tag on the beach–it’s a rare event but it has happened–please call the monk seal hotline to report it.)

Photo credit: D. Lee

Basically, seals molt, because their coat gets dirty. After spending long bouts of time at sea, algae will often grow on their fur. If you see a seemingly green-colored seal, you’ll know he or she is nearing his/her molt.

After molting, monk seals regain their dark gray to brown color on their dorsal (back) side and a light gray to yellowish brown color on their under (ventral) side. This difference in coloration is known as “countershading.” From below, the seal’s light belly blends in with the sunny surface of the ocean. From above, the seal’s darker back is closer in color to the dark ocean floor. This serves as camouflage for seals. It helps them sneak up on prey, as well as, hide from sharks and other predators.

Last fall, the Hawaiian Monk Seal Research Program placed dive recording tags on two monk seals that make their home in Kauai waters. We briefly wrote about it here. During one recording period, the two seals (R1KT and R7AA) both made numerous dives deeper than 150 meters (492 feet). One bottomed out at 170 meters (557 feet) and the other at close to 200 meters (656 feet).

These are mammals diving to 500 feet on a single breath of air. But that’s not unusual for monk seals. In fact, the deepest known dive for a monk seal occurred in 2003 when scientists in a Pisces submersible descended to a depth of 543 meters (1,781 feet). They were studying deep sea corals, submarine canyons, and seamounts when a Hawaiian monk seal swam into their field of view. The on-board microphone captured their reaction. It went like this:

“Whoa.”

“What’s that?”

“That’s a monk seal.”

“Oh my god.”

“No way.”

“Look it. Right in front of us.”

“No way.”

“Oh my god.”

So, how do they do it? How do monk seals dive to depths of 1,781 feet?

There are numerous physiological responses involved; collectively the process that allows monk seals to dive deep is known as “mammalian diving reflex.” It involves the respiratory and cardiovascular systems. Typically, before a dive, seals exhale completely. This allows their lungs to completely collapse and avoid gas transfer at depth that could cause nitrogen narcosis. Then, holding their breath, the heartbeat slows from about 125 beats per minute to as low as 10 beats per minute. This is known as bradycardia. A slowing heart rate reduces oxygen consumption. Too, blood is diverted from the limbs and all organs except the heart and brain. This is known as blood shift. It’s accomplished through a process known as peripheral vasoconstriction. Too, diving mammals have high blood volume. That is, elevated hemoglobin and myoglobin levels, which provides greater oxygen storage. The whole idea is to conserve oxygen consumption, so the seal can dive deeper and longer.

Simply, they can hold their breath, slow their heart rate, and direct blood to just the heart and brain. This also helps explain their torpedo-like shape and abbreviated pectoral fins.

In September, two Hawaiian monk seals were outfitted with dive recording tags that not only capture the seals’ location but time spent hauled out, time at the surface of the sea, and time spent (and depth of ) diving. Data from the tags is transmitted whenever the seals come within range of a cell phone tower. The instruments tags were affixed to the middle of the seals’ backs using an epoxy. When the seals next molt, the tags will fall off.

This first graphic shows the movement of the two tagged seals. The yellowish-green dots represent R1KT, a male. The red dots represent R7AA, a female. The graphs give us a look into three week’s worth of these two seals’ lives.In the graph on the right, we see the depths of R7AA’s dives. She records several dives in excess of 150 meters, but the vast majority of her dives log at under 100 meters of depth.

On the other hand, the majority of R1KT’s dives record upwards of 150 meters. There are numerous factors that could explain the differences. One, age. R7AA is a juvenile; whereas, R1KT is older. Too, underwater topography may affect their dive depths. Generally, according to science, monk seals like to forage on or near the ocean floor. They are generalist feeders and their diet includes a variety of fishes (eels, wrasses, squirrelfish, soldierfish, triggerfish, parrotfish), cephalopods (octopus and squid), and crustaceans (crab, shrimp, and lobster). Diet studies indicate they prefer prey that hides in the sand or under rocks, unlike most of the locally popular game fish (e.g. ulua, papio and ʻoʻio) and the proportion and type of prey consumed varies significantly by island, year, age and sex.

A yearling female that showed up on our north shores in late June, made her way south in August. She hauled up several times at Lawai Beach where the NOAA Science Center scientists and veterinarian were able to capture and examine her healing abscess and, with the Kauai team, flipper tag her (7AA/7AB).

PC: B. Becker

She was given a long acting antibiotic, and fitted with a cell phone transmitter, so we can monitor her movements, foraging and follow her health.

Seals of Concern Updates

PC: M. Olry

RH38: A female yearling seal that was underweight, was transported August 11 by US Coast Guard C-130 to Kona, where she is being rehabilitated at Ke Kai Ola, the Hawaiian monk seal hospital. Her admission weight was 40 kg and she was treated for tapeworms, which were causing her to do poorly. She is eating well, and now is at 46 kg. She has two companions from the NWHI, one admitted in June and the other in August. The plan is to complete her treatment for tapeworms and to allow her to gain enough weight to insure her success after release in another month or two.

Hooked SealsThe adult male seal that was hooked in his back threw off the hook, and continues to be seen at Poipu, he is now freshly molted and known as Temp331.

An unknown seal was reported by a fisherman on the rocks at Kaumakani point last week. The hook is in the right corner of the mouth and is non-life threatening. We do not know of the identification of this seal, whether it has tags or its sex. It may be a young adult or subadult, possibly a Ni’ihau seal, so keep a lookout!

Seal Research

PC: B. Becker

The NOAA Pacific Islands Science Center research biologists were on Kauai for a week working with the Kauai team to find a subadult or adult male seal to deploy a new streamlined “critter” camera. Searching all coasts, practically all of Kauai’s seals were sighted! Many of the mature males were either starting or finishing their molts, so they were not candidates.

PC: B. Becker

Finally R1KT (molts in Dec.) was found on a quiet sandy beach. The team was able to capture him and place a camera (in front) and cell phone transmitter to help relocate him to remove the camera three days later to retrieve the footage. The instruments not only gave a visual video record of movements, but also location, depth of dives, time periods and speed! We look forward to learning what R1KT has to teach us!

We thank the many volunteers that searched with us and responded to mul- tiple seal haul outs to find a good candi- date. We also found a new large adult male, fairly clean, without scars, not known to our records. With additional experienced seal handlers, we were able to capture this seal and tag him. He is now called R2XS with tags (2XS/2XR).

Famous Waikiki Pup TranslocatedRH58’s weaned pup, is now known by her tags at RJ58 and still remembered as Kaimana, the Ha- waiian name for her natal beach. Because of vari- ous risk assessments and considerations, she was translocated to a north shore beach to put her in a safe location, where she could interact with other seals and safely forage and explore without the human crowds and dangers at Waikiki.

Additional Marine Animal News
The State Board of Land and Natural Resources Approves New Boating Rules that will prohibit feeding of wildlife or feral animals, and abandoning animals, and creating or contributing to colonies at any property under the boating division’s jurisdiction. These new sections were added in response to complaints about increased feeding of feral animals at boating facilities, which creates potentially unsafe and unsanitary conditions and endangers sea life.

The board approved both amended rules but deferred implementation of a provision that would allow disposal of feral or abandoned animals at state small-boat harbors until Jan. 1, 2019. The delay was to give time for the boating division to work with animal caregivers to come up with a viable plan to relocate colonies of feral and abandoned animals to areas outside of the small-boat harbors.

NOTE: Cats are the only reproductive host of the parasite toxoplasmosis, which has killed monk seals, and continues to threaten human and other marine mammal health. Click here.